Mass culturing of Spirulina (Arthrospira) (Cyanobacteria) from the laboratory to the production plant: 30 years of research

From its modest beginnings, when Chlorella was first mass cultured in the early 1960s, mass culturing of microalgae has emerged as a specialized industry the world over. It is used to produce health food, food additives, animal feed, biofertilizers and an assortment of natural products. Spirulina, what is now known scientifically as Arthrospira, was the second micro algal species to be mass cultured and marketed as a food supplement. Spirulina gained the initial interest of scientists due to its overall nutritional qualities, which include a high protein content (60 to 70% of dry wt.), low fat and high vitamin content, particularly B12. Only later was attention given to specific nutritional components of the alga, such as its concentrations of gamma-linoleic acid (GLA) and phycocyanin. Today, Spirulina is commercially cultivated the world over, with a total annual production of more than 3000 MT and a potential exceeding 4000 MT. Spirulina products in the form of spray-dried powder, pills, capsules and various food products formulated for human consumption are produced in Chile, China, India, Japan, Taiwan, Thailand and the USA, mainly for the health food market. Small amounts of Spirulina are extracted for the production of phycocyanin, known commercially as 'lima blue' and used as a blue colorant for food and cosmetics. In addition, some Spirulina products are fortified with extracts of various herbs as well as some vitamins and minerals and sold as relief for premenstrual syndrome. It is interesting to note that the idea of algal mass culture was adopted by two entirely different consumer blocs: on the one hand - affluent Western societies, particularly vegetarians looking for natural food stuffs and health and health-food additives for their diet and on the other hand - developing societies in their search for a rich source of protein that can be produced under local conditions and with local resources, i.e., on marginal land and using saline water not suitable for conventional agriculture. This reflects a unique feature of this biotechnology, its adaptability to different operation skills and scenarios, which emphasizes the feasibility of incorporating this biotechnology into small industries in developing countries. Much progress has been made since the beginning of this technology some 30 years ago, mainly in the management of outdoor cultures. Current practices are based on a better understanding of the biology of dense cultures grown on a large scale, as well as of the technological aspects of this biotechnology, such as pond design, mixing systems, and modes of harvesting. Today, there is no doubt that Spirulina is a viable biotechnology, and in terms of total biomass traded in the world market, it exceeds that of Chlorella. The next challenge to the Spirulina mass culturing industry lies in the ability to develop new markets promoting Spirulina in the feed additive market for aquaculture and poultry will significantly increase the total demand. Thus, the future of this industry rests, to a large extent, on the ability to reduce production costs and thus make algal biomass a commodity traded in large quantities. This can be achieved only if further research efforts are invested to overcome the main limitations of the industry. These include the search for improved strains that are more suited to the different climatic conditions of this global technology, as well as overcoming contamination problems either by strain selection or pond management.